This invention relates to an electrical lead for connecting animal tissue to an electrical stimulation generator, and more particularly to an endocardial lead having a retractable helix for fixation to the cardiac tissue.
The screw-in concept has long been known as a viable means for achieving positive fixation in atrial and ventricular pacing applications. However, certain drawbacks do exist in the current state of the art devices, such as overall size, exposed fixation means, fluid leakage and point of stimulation being remote from point of fixation. At the present time, it appears that no one design has been able to overcome all of these drawbacks.